American foulbrood, European foulbrood and sacbrood. These cause 
loss to the beekeeper by causing the death of developing brood, 
thus reducing the colony in strength so that it becomes unproductive 
and may fall a prey to wax moths or die from depletion. These 
diseases also cause loss to the beekeeper by increasing the labor 
necessary to keep them under control. 
American Foulbrood 
This disease is caused by bacillus larvae, White*, an organism 
which is harmless except to the baby bees. American foulbrood was 
so named because it was first seriously studied in America. Death 
abe, Normal expbings. 
ef. Sinton and pofersted capbings. 
9s,. Feboe fated by disease. 
‘hr, Scales from dried-down larvag 
PALM G, Diseased Varvec 
Fig. 38. American foulbrood (redrawn). 
from the attacks of this organism occurs principally after the develop- 
ing bees have been sealed in the cell. The normal color of healthy 
larvae is pearly white, but when attacked by this disease the larvae 
become a light brown, later turning to dark brown. Since death 
as a rule does not occur until after the larva is sealed, at that 
time it is lengthwise of the cell with the posterior portion slightly 
elevated against the cell base. (Fig. 38). Therefore, the remains of 
larvae dead of this disease are usually on the lower cell wall. This 
position is best observed by holding an infected comb upright in such 
a way that the light comes from over the shoulder and looking at the 
*White, G. F., 1907. The cause of American Foulbrood. 
ment Agriculture. Bureau Entomology Circular, 94, 
ot 
inited States Depart- 
